A variety of perforating and other fracturing techniques are conducted in wellbores drilled in geological formations. The resulting perforations and/or fractures facilitate the flow of desired fluids through the formation. For example, the production potential of an oil or gas well can be increased by improving the flowing ability of hydrocarbon based fluids through the formation and into the wellbore. In some applications, however, difficulties arise in initiating and achieving desirable fractures to facilitate fluid flow.
In horizontal wells, for example, it is common to use a slotted or pre-perforated liner. This type of liner causes difficulty in using a slurry within the annulus to fracture the formation. The difficulty arises because the pressure drop of the annular flow causes the pressure to be higher at the heel of the horizontal wellbore then at the toe of the horizontal wellbore. Attempts have been made to cut slots or cavities into the formation around the wellbore to facilitate fracture by acting as a fracture initiation site. However, such attempts have suffered from an inability to adequately control and accomplish the desired cutting into the formation.